If you cave into her on this (and I suspect you will), then at a MIMIMUM those funds (the add'l debt put onto your line-of-credit) should come out of HER half of the proceeds when you sell your house.
Essentially, once a spouse is either wayward or runs away, the LBS needs to draw a financial line in the sand, and separate the finances. This is her fantasy, and her journey, and you shouldn't have to pay for it, past behavior notwithstanding. If you are STILL being abusive to her in any way, or if her presence in your home is a danger to herself, then my opinion would obviously be completely different.
